If you want to bring meat products try and get it vacuum packed and place it in your checked baggage. The temperature in the hold is usually cold enough to keep it going for a good long time. I did this all the time when brining (the best in the world) meat from Ireland to France when I lived on the emerald Isle.

If you can get the these vacuum packed as well you're golden. I do this when I bring cheese from Switzerland to Scandinavia and works a treat every time. Also, I pack this in the checked baggage.

No need to declare farm produce as long as it is EU stamped and/or you can show that EU tax has been paid should it come from abroad.

You can get these Freezer-cooling blocks for literally 1 euro each, they will help to keep the temperature down.

You keep these for about 6 hours in the freezer, after which they are frozen solid and will stay cold for a long time. You can pack them together with the food and keep it for quite some hours of travel. This way I have successfully transferred cheeses on a 5 hour bustrip + 3 hour flight, and 2 hour train ride. (all in a row).

Only downside is that, due to the extra liquid, you will need to check your bags.